Questions have been raised about its environmental impact, and the likelihood of its estimated $4 billion cost blowing out by some billions. Last week, National’s energy and resources spokesman Stuart Smith added to the disquiet about the proposal by saying the party would rule out public sector investment in it.
He called the proposal unnecessary and undesirable and a pet project which, rather than being investigated, was being justified by feasibility studies under way.
The New Zealand Battery Project was set up to find a solution to the "dry year problem" when existing hydro-power catchments do not receive enough rainfall or snowmelt and storage lakes run low. At the moment the coal-burning Huntly Power Station provides back-up, something which is not environmentally acceptable .
Its continued use would prevent the country reaching its goal of 100% renewable electricity generation by 2030 (but even if the Lake Onslow project were to proceed it seems highly unlikely it would be up and running by then).
Under the proposal, a dam would raise the existing man-made lake near Roxburgh and water would be pumped up from the Clutha River when electricity was surplus.
Water would then be released down a tunnel and through a pumphouse to generate power when it was needed — notably in dry years when the South Island hydro lakes are low.
It is a massive project. Should it proceed, it would be our biggest infrastructure project since the 1980s.
Whether the feasibility studies for phase 1 of the project justify anything is unknown. Their details, including the environmental impact of the project, have yet to be released. They were to have been considered by Cabinet last month but that has been delayed until this year. Such delays in decision-making will not help the uncertainty for those whose land would be affected.
These have not been spelled out, but Forest & Bird has already raised concerns about the loss of nationally important wetlands affecting the habitat of a critically endangered fish species, and the impact on the Clutha River. The Otago Fish and Game Council is worried about the loss of trout spawning habitat.
Although the battery project is described as investigating the feasibility of a pumped-hydro scheme at Lake Onslow and other locations around the country, as well as other solutions, we have heard little about the other options or locations.
Non-hydro options have been considered, with hydrogen, flexible geothermal generation and bioenergy assessed as having the most potential, but none were seen as having the ability to provide a single solution to the dry year problem.
The first phase also explored the impact long-term, large-scale storage would have on the electricity market. This would be examined further in Phase 2. The issue of whether it might be used as a price-fixing mechanism is already concerning existing generator-retailers, although it might be welcomed by consumers.
It is hard to gauge if enough attention has been paid to myriad less "think big" solutions because of the paucity of detail to date.
Mr Smith’s reasoning that if the project was such a great one the private sector would be breaking its neck to build it might not hold water, but the idea any future National government would not fund it will buoy those already questioning the project’s value.
If Cabinet decides the Onslow project should proceed to Phase 2 and the development of a detailed business case, and the opposition gains momentum, could it become an electrifying election issue?
